The present invention relates to an environmental air humidification and cooling system.
Certain closed environments such as computer rooms require air conditioning that has a fixed cooling and rigid humidity control for a proper machine environment. In known systems, dehumidification and cooling are achieved by the control of cooling coils and humidification is achieved by evaporating water within the body of the air conditioning unit by the use of immersion heaters or evaporation lamps or in some cases steam injection.
In prior art systems, air is heated by equipment operated within the computer room and is returned to the air conditioning unit. This return air is drawn through filters and blown through cooling coils. The cooling coils are temperature controlled to satisy either the leaving temperature or the room temperature directly. The humidity in the room is sensed and the unit will dehumidify or humidify to maintain the room set point. By use of the air conditioning controls during humidification, the air must be far enough from saturation to accept moisture and this causes subcooling to accomodate the additional moisture and the inherent temperature rise.
In the known air conditioning units, air is cooled in condenser units which are completely dependent on the ambient dry bulb temperature of the air therein. Thus, if the air that is entering the condenser has been heated by equipment in the environment, or if it is outside air during the hot summer period, the air conditioning unit has an overall lower performance and lower efficiency.
Closed environment air conditioning systems also require winter cooling as well as winter humidification. In the winter, air conditioning systems have normal operating ranges of from 74.degree. to 78.degree. F. and from 20 to 16% relative humidity. In environments of this type, such as in buildings, it can be shown that the internal vapor pressure is essentially in equilibrium with the external vapor pressure. Additionally, there is a stack effect created by the cold heavy air mass against the warm dry air building. Therefore winter humidification as well as cooling is a desirable characteristic in the system.
Known devices that are used for positive humidity control for winter humidification have significant energy consumption. For example steam grids add humidity effectively but can increase steam consumption 5 to 6 percent, as well as boiler water make up rates. Some steam systems are sources of odors due to the chemical treatment of the steam. Air washers of the cellular or spray type usually require additional and significant fan horsepower and many necessitate usage of preheat coils as well.